Spot the Design Weakness - For Northern Climates

If we had a dime for each weak building assembly detail we saw, we’d be rich. In our 14 years of diagnosing comfort problems for clients; the exposed floor ranks as one of the most stark discomfort features of a home, new or old.

Walking home from the coffee shop Sunday and came across the feature below. Have a look at the photo and see how many design errors you can pick out:

Even 2LBS spray foam won’t ward off the discomfort in this small but significant exposed floor. How can it, the poor design will handicap it and soon enough all will be covered with lovely aluminum perforated soffit and who will know better.

So here’s the blow by blow, spray foam doesn’t stick well to oiled metal, there’s not enough room between the bottom of the duct and future soffit and though code does allow R12 they won’t get 2″ on the bottom. The duct will lose flow and warmth as it passes so close to the outdoors only to come back in. It runs close and may even touch 2 uninsulated metal beams. Lastly, let’s keep our finger’s crossed that the open joist cavity above the stone wall is continuously sealed otherwise that whole floor cavity above the entire foyer will feel cold to the touch on both sides (main floor and second).

As for the pot lights in the eaves, they are hard to change when they burn out and often create too much heat enough at times to create and ice dam.

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Won't matter how energy efficent or not a house is, if water proofing and condensation isn't the first priority.

Bigger problem for the entire building is the stucco finish. In a Northern (freeze / thaw) they crack, and it seems most folk don't think you need to maintain stucco even as much as wood siding, like painting to seal the hairline cracks before they become big cracks. Stucco chock full of synthetic ad mix can act as a pretty good vapor barrier and condensing surface too. Of course, what I'm looking at is probably the facing of a EFIS system in which case all I can say is ekkkkk!

As an architect, I'll question the overhang, dormers and 2nd fl soffit cans. I like boxes suspended in space as much as the next guy, but the fringe of roof and soffit just cries out for a couple of posts, which could be glazed between, and you have a vestibule, maybe even a sun room that could be a net heat generator, and mitigate coldness of the overhang. Dormers, I'm betting not another floor, but part of cathedral ceiling, and the cave man in me loves that the living in a cavern feeling, but, indefensible energy wise. The 2nd fl cans are just lame, as pointed out. Though, I've seen such for those who had "security" problems, which as sad as that might be, could justify the cans (and luckily these clients could always afford to hire folk to replace the bulbs).

I agree, we typically collaborate with Architects and Design-Build contractors to 'head these off at the pass.'

If you asked me to design a house, I could. I could also build it. It'd be super efficient and super comfortable but it would look like an old Volvo.

That's why we need architects, they know how to design and use space elegantly; a skill I don't have. But I do know building envelope weakness and that's where boots on the ground can help the designer if they don't have the experience of fixing and witnessing countless failures.

And the homeowner reported an immediate and noticeable improvement in comfort, both evenness and balance.

One week after single digit temps every night I had to turn the other furnace on for a few days because the house slid back. I think this may have been due to Time Warner's crappy thermostat which seems to have a mind of it's own. Had the temp been left constant, the 70k output may have been sufficient to carry this HUGE house.

When I've aggressively sized below Manual J in the past, surprising energy savings have been another positive result: http://bit.ly/meterpictures

Jim, 95% of overhangs you see lead straight into the home. My brother could freeze icetrays on his kids floors until he addressed it. My mother and every one of the identical $250k condo's in her neighborhood all have garage attics connected to the second floor - no box band: